Noncompliance with research protocols can be especially problematic, potentially resulting in unusable trial data. Typically, subjects are given a paper-based diary and asked to make scheduled entries regarding their illness, medication effects, as well as other data entries recording events as they happen. Subjects must keep track of the time of day, where they are in the sequence of events for any given day, and the appropriate procedures they are to follow across days. Many subjects do not complete their diaries or complete their diaries long after the events that are to be logged. Eight studies have examined compliance rates of these paper diaries by covertly collecting data about the timeliness of entries. A dramatic difference between subjects' reported versus actual compliance was observed. Whereas the paper diaries appeared to indicate high rates of compliance (88%), the actual rates of compliance were significantly lower (54%).
Evaluation of subject compliance with research protocols is often performed by examining only one variable at a time. Such evaluation is not empirically derived by quantitative analysis of existing datasets. Instead the evaluation relies on the researcher's judgment and biases to determine whether and what type of corrective action is required. Furthermore, evaluation of subject compliance with clinical trial protocols has typically not taken into account the domain of the clinical trial or the characteristics of the subjects.